A silicon controlled rectifier including a semiconductor substrate, first and second semiconductor wells, first and second semiconductor regions, third and fourth semiconductor regions and a silicide layer is provided. The first and the second semiconductor wells are formed in the semiconductor substrate. The first and the second semiconductor regions are respectively formed in the first and the second semiconductor wells in spaced apart relation. The third and the fourth semiconductor regions are respectively formed in the first and the second semiconductor wells. The silicide layer is formed on the third and the fourth semiconductor regions. The silicon controlled rectifier is at least suitable for high frequency circuit application. The silicon controlled rectifier has a relatively low trigger voltage, a relatively high electrostatic discharge level, and a relatively low capacitance.